CONTROL OF HERBICIDE RESISTANT ECHINOCHLOA ORYZOIDES WITH PRE AND POST EMERGENT HERBICIDES BASED ON THE LEAF STAGES

The effect of weed control was investigated, based on the leaf growth stages and/or several different herbicide treatments, for an integrated weed management of herbicide resistant Echinochloa oryzoides in a rice field. The effectiveness of soil-applied herbicide treatments for pre-emergent control of E. oryzoides resistant to herbicides was very high with oxadiargyl 1.7% EC, oxadizon 12% EC, and fentrazamide·oxadiargal 3.3% EC. Pentaxazon 5% SC achieved over 98% of weed control, although some E. oryzoides emerged 31 days after the treatment. Up to the 2nd leaf growth stage of E. oryzoides, six herbicides, azimsulfuron·carfenstole 1.05% GR, bensulfuron-methyl·benzobicyclone· mefenacet 24.52% SC, bensulfuron-methyl·fentrazamide 7% SC, bensulfuron-methyl· mefenacet·oxadiargyl 21.6% SC, benzobicyclon·mefenacet·penoxulam 21.5% SC and mefenacet·pyrazosulfuron -ethyl 3.57% GR achieved 100% control. However, only two herbicides, benzobicyclone·mefenacet·penoxulam 21.5% SC and mefenacet· pyrazosulfuron-ethyl 3.5% GR could control E. oryzoides up to the 3rd leaf growth stage. The study indicates that it is very important to select the right herbicides for treatment and apply them at the correct timing to achieve a high level of control of E. oryzoides resistant to ACCase- and ALS-herbicides.